1. Field of the Invention
The present invention relates generally to a sheave assembly, and particularly to a sheave assembly having replacable arcuate inserts disposed around a sheave rim, forming an annular wear surface around which a line or cable travels.
2. Description of the Prior Art
Sheaves are commonly used to guide rope or cable under heavy strain. The sheave rim or wear surface, around which the cable travels, wears out quite rapidly due to the friction caused by its incessant rubbing engagement with the rope or cable. To avoid having to replace the entire sheave, which is expensive and difficult to replace, sheaves having a replaceable rim or wear surface have been developed.
To replace the wear surface (rim) of some sheaves, it is necessary to disturb the position of the rope or cable. Indicative of this are sheaves formed with their wear surface sections attached end to end, as disclosed by U.S. Pat. No. 449,322 to Harris and Thomas, U.S. Pat. No. 192,562 to Bushnell and U.S. Pat. No. 3,427,892 to Leonard et al., as well as sheaves held together by cross bolts, as disclosed in U.S. Pat. No. 2,685,801 to Tishman.
Other types of sheaves have replaceable wear surface sections bolted to the rim of the sheave. Representative of this type of sheave are U.S. Pat. No. 829,898 to Schultz and U.S. Pat. No. 425,734 to Birch.
U.S. Pat. No. 469,512 to Buswell discloses a sheave having side flanges adjacent the sheave rim, defining a central groove around the periphery of the sheave. Replaceable wear surface inserts, each insert comprising separate side flange members and a separate wear surface element, are assembled and fixed within the central groove by cross bolts threaded through a sheave side flange into engagement with both insert side flange members.
U.S. Pat. No. 2,637,214 to Morey discloses wear surface segments fastened around a sideless sheave rim by fasteners such as hoops, straps or cables. However, the segments are without lateral support when disposed around the sheave rim.
U.S. Pat. No. 3,606,257 to Wilson discloses elastomeric or elastic band type members that extend around the sheave. These members act as a slip clutch, and not as a device for holding the sheave sections together.